From the same larvicidal experiment, median lethal concentration (LC50) was calculated. The mortality values were analyzed through SPSS software using Probit analysis35. Log concentrations and probit obtained from the SPSS software (version 20) were then analyzed using MINITAB software. This LC50 was considered the LC50 for F0 generation.
Epa probit analysis program free 139
The acute toxicity of three formulations of commercial detergent (ROMA, FOCA and BLANCA NIEVES) was evaluated using the polychaete Capitella sp. C in static bioassays over a 48-h exposure period. The probit method was used to determine the median lethal concentration (LC50) of each formulation as a whole as well as the LC50 of the active ingredient, linear alkylbenzene sulfonate (LAS), using 95 % confidence intervals. The formulations and LAS showed LC50 values of between 70.79 and 147.91 ppm and 15.48 and 22.38 ppm, respectively, at 48 h. FOCA was the most toxic detergent, followed by BLANCA NIEVES and finally ROMA. The variation in the toxicity of the three detergents could have been caused both by differences in the relative concentrations of the anionic surfactant LAS contained in each formulation and the presence of other ingredients (enzymes, sodium silicate, sodium tripolyphosphate, bleachers and perfumes) which can also increase formulation toxicity. Correlation analysis revealed that percent mortality of Capitella sp. C increased with increase in the concentrations of the detergent over the 48-h exposure period. The risk quotient was greater than one for all three evaluated detergents, indicating that there is a high risk that they adversely affect the aquatic biota, particularly sediment-dwelling organisms such as the test species.
All statistical analyses were performed with SPSS statistical program. All experimental data were expressed as mean standard deviation (SD). Significant differences between experimental and control groups were compared by One-Way ANOVA (analysis of variance) followed by Least Significant Difference (LSD) ( and 0.001) using the Statistics Package (SPSS) program Version 7.
Larvicidal activity was carried out as described by the WHO [17] with minor modifications as described by Rahuman et al., [18] using third instar larvae. Four different concentrations; 0.125, 0.25, 0.5 and 1 mg/mL were tested. The extracts were prepared in 0.1 mL of DMSO and 99.9 mL of distilled water contained in a 250 mL beaker. This solvent system in a similar ratio served as the control. Three batches of twenty larvae were used for all the experiments and the number of dead larvae in each test was counted and removed after 24, 48 and 72 h of exposure. The mortality data were subjected to Probit analysis to calculate lethal concentration values (LC50 and LC90) and lower and upper 95% fiducial limits. LC50, LC90 and Chi-square values were calculated using the EPA (U.S. Environmental Protection Agency) computer Probit analysis program (version 1.5).
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